1. Field of the Invention
The present invention relates to a display device comprising a plurality of light sources such as LED's disposed in a predetermined pattern for displaying a symbol such as a numeral or a character by turning on selected light sources. Further, the present invention relates to a display device assembly comprising a plurality of the above display devices mounted on a mother board.
2. Background Art
Conventional display devices of the above type include a seven-segment LED display device in which seven, bar-shaped, light emitting elements are disposed in a pattern of a numeric FIG. 8 for displaying a desired numeral. Also included is an eight-segment LED display device which is a seven-segment device added with another light emitting element representing a decimal point. Further included is a dot-matrix type LED display device in which a plurality of dots each made of a light emitting element are disposed in a matrix pattern for displaying a symbol such as a numeral or a character. Each of these display devices is mounted on a mother board, and is supplied with electric power through the mother board. Conventionally, mounting of these display devices is made as follows for example.
Specifically, referring now to FIG. 4, when a display device 1 has outer edges formed with a plurality of terminals 10 each connected to one of the light sources, each of the terminals 10 is bonded to a terminal portion formed on the mother board by soldering. More specifically, each of the terminals 10 of the display device 1 or each of the terminal portions on the mother board is coated with solder in advance, and then, the display device 1 is aligned with and lowered on the mother board. Next, the solder is re-melted, and then cooled to set, completing the mounting of the display device 1 to the mother board.
Now, in order to display a plurality of numerals or characters simultaneously, a plurality of the display devices must be disposed in a line and/or row. In such a case, each of the display devices 1 should be disposed as closely to adjacent display devices as possible so that the plurality of the numerals or characters do not appear too far away from each other giving a poor look.
There is a problem, however. Specifically, when using the display device 1 in which the plurality of terminals 10 are formed along the outer edge portions, solder portions 11 stay extended out of the outer edge portions in each of the display devices 1. For this reason, as shown in FIG. 5, each display device 1 must be spaced from another by a certain distance. Since it is impossible to dispose the display devices 1 closely to each other, it is impossible to make an outer edge of one display device 1 abut on an opposing outer edge of an adjacent display device 1.